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DDogleg Numerics is a high performance Java library for non-linear optimization, robust model fitting, polynomial root finding, sorting, and more.
/*
* Copyright (c) 2012-2015, Peter Abeles. All Rights Reserved.
*
* This file is part of DDogleg (http://ddogleg.org).
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.ddogleg.stats;
import org.ddogleg.sorting.QuickSelect;
import org.ddogleg.struct.GrowQueue_F64;
/**
* @author Peter Abeles
*/
public class UtilStatisticsQueue {
public static double mean( GrowQueue_F64 list ) {
double total = 0;
for (int i = 0; i < list.size(); i++) {
total += list.data[i];
}
return total / list.size();
}
public static double variance( GrowQueue_F64 list , double mean ) {
double total = 0;
for (int i = 0; i < list.size(); i++) {
double d = list.data[i] - mean;
total += d*d;
}
return total / (list.size()-1);
}
public static double stdev( GrowQueue_F64 list , double mean ) {
return Math.sqrt(variance(list,mean));
}
public static double fraction( GrowQueue_F64 list , double fraction ) {
int k = (int)((list.size-1)*fraction+0.5);
return QuickSelect.select(list.data,k,list.size);
}
}